Analysis of using XML Schemas Datatypes in the XForms Data Model

2.1 Similarities

• All datatypes have a value facet which is similar to the xsd:enumeration facet

• All datatypes have a default facet is similar to an XML Schema attribute declaration where use="default" and value is set to the default attribute value, or an XML Schema element declaration where default is set to the default element value.

2.2 Differences

• XForms range facet allows type values to be one of an enumerated set of literal values or a free form value. There is no equivalent XML Schema facet.

• For all types but string the XML Schema xsd:pattern and xsd:enumeration facets have no counterparts in XForms

• XForms has no provision for the reuse of user-defined datatypes.

• XSchema has the ability to derive any SimpleType "by list".

2.3 Usage Comparison

<xsd:element name="maritalStatus" default="married">
  <xsd:simpleType base="string">
    <xsd:enumeration value="single"/>
    <xsd:enumeration value="married"/>
  </xsd:simpleType>
</xsd:element>

<string name="maritalStatus">
  <value>single</value>
  <value>married</value>
</string>

3.1 Declared as a SimpleType

<xsd:simpleType name="string" base="xsd:string"/>

3.2 Similarities

• Regular expression pattern facet support is identical to the xsd:pattern facet, however XForms may drop this in favor of the simpler mask facet.

• min and max facets are identical to the xsd:minLength and xsd:maxLength facets

3.3 Differences

• mask facet has no XML Schema counterpart

• xsd:length facet has no XForms counterpart

• XForms has no concept of string ranges (xsd:minExclusive, xsd:maxExclusive, xsd:minInclusive, and xsd:maxInclusive)

3.4 Usage Comparison

<xsd:element name="socialSecurityNumber">
  <xsd:simpleType base="string">
    <xsd:pattern value="\d{3}-\d{2}-\d{4}"/>
  </xsd:simpleType>
</xsd:element>

<string name="socialSecurityNumber">
  <mask>nnn-nn-nnnn</mask>
</string>

4.1 Declared as a SimpleType

<xsd:simpleType name="boolean" base="xsd:boolean">
  <xsd:enumeration value="true"/>
  <xsd:enumeration value="false"/>
</xsd:simpleType>

4.2 Similarities

• Use of 'true' and 'false' literals

4.3 Differences

• XML Schema allows '0' and '1' in addition to 'true' and 'false'

4.4 Usage Comparison

<xsd:element name="isRequired" default="true">
  <xsd:simpleType base="boolean"/>
</xsd:element>

<boolean name="isRequired" default="true"/>

5.1 Declared as a SimpleType

<xsd:simpleType name="number" base="xsd:decimal"/>

5.2 Similarities

• min and max facets are identical to thexsd:minInclusive and xsd:maxInclusive facets

• decimals facet is identical to thexsd:scalefacet

5.3 Differences

• Setting the XForms integer facet to 'true' is analogous to setting the XML Schema xsd:scale facet to 0

• xsd:precision facet has no counterpart in XForms

• XForms has no concept of exclusive numeric rangesxsd:maxExclusive, xsd:minExclusive facets)

5.4 Usage Comparison

<xsd:element name="floor">
  <xsd:simpleType base="number">
    <xsd:scale value="0"/>
    <xsd:minInclusive value="1"/>
    <xsd:maxInclusive value="200"/>
  </xsd:simpleType>
</xsd:element>

<number name="floor" integer="true" min="1" max="200"/>

6.1 Declared as a SimpleType

<xsd:simpleType name="money" base="xsd:decimal"/>

6.2 Similarities

• min and max facets are identical to thexsd:minInclusive and xsd:maxInclusive facets

• decimals facet is identical to thexsd:scalefacet

6.3 Differences

• XForms currency facet has no XML Schema counterpart

• xsd:precision facet has no counterpart in XForms

• XForms has no concept of exclusive numeric ranges (XML Schema facets:maxExclusive, minExclusive)

6.4 Usage Comparison

<xsd:element name="price">
  <xsd:simpleType base="money">
    <xsd:scale value="2"/>
    <!-- cannot specify currency -->
  </xsd:simpleType>
</xsd:element>

<money name="price" decimals="2" currency="USD"/>

7.1 Declared as a SimpleType

<xsd:simpleType name="date" base="xsd:date"/>

7.2 Similarities

• Lexical format is identical when XForms precision facet is set to 'years'

• min and max facets are identical to thexsd:minInclusive and xsd:maxInclusive facets

7.3 Differences

• XForms precision facet has no direct counterpart in XML Schema. Setting precision to 'months' is analogous to constrainingxsd:duration to 'P1M', and settingprecision to 'days' is analogous to constrainingxsd:duration to 'P1D'.

• XForms allows the use of relative durations ('+P2D') for both themin and max facets. XML Schema requires that ranges are specified using absolute values.

• XForms allows the literal value 'now' for both theminandmax facets. XML Schema has no concept of 'now'.

• xsd:precision facet has no counterpart in XForms

• XForms has no concept of exclusive temporal rangesxsd:maxExclusive, and xsd:minExclusive)

• XML Schema xsd:period facet has no counterpart in XForms

7.4 Usage Comparison

<xsd:element name="birthDate">
  <xsd:simpleType base="date">
    <!-- cannot specify a maximum of "now" -->
    <xsd:maxInclusive value="2000-05-15"/>
  </xsd:simpleType>
</xsd:element>

<date name="birthDate" max="now"/>

8.1 Declared as a SimpleType

<xsd:simpleType name="time" base="xsd:time"/>

8.2 Similarities

• Setting the XForms precision facet to 'hours', 'minutes', or 'seconds' is roughly analogous to setting the XML Schema xsd:period facet to 'PT24H', 'PT60M', and 'PT60S', respectively.

• min and max facets are identical to thexsd:minInclusive and xsd:maxInclusive facets

8.3 Differences

• xsd:precision facet has no counterpart in XForms

• XForms has no concept of exclusive temporal rangesxsd:maxExclusive, and xsd:minExclusive)

8.4 Usage Comparison

<xsd:element name="meetingTime">
  <xsd:simpleType base="time"/>
</xsd:element>

<time name="meetingTime"/>

9.1 Declared as a SimpleType

<xsd:simpleType name="duration" base="xsd:timeDuration"/>

9.2 Similarities

• Lexical values are identical.

9.3 Differences

• XForms precision facet has no counterpart in XML Schema.

• XForms has no concept of temporal duration rangesxsd:maxInclusive,xsd:minInclusive,xsd:maxExclusive, andxsd:minExclusive)

9.4 Usage Comparison

<xsd:element name="runningTime">
  <xsd:simpleType name="duration"/>
</xsd:element>

<duration name="runningTime"/>

10.1 Declared as a SimpleType

<xsd:simpleType name="uri" base="xsd:uriReference"/>

10.2 Similarities

• Lexical values are identical.

10.3 Differences

• While the XForms scheme facet has no direct counterpart in XML Schema, the xsd:pattern facet can be used instead.

• xsd:length, xsd:minLength, andxsd:maxLength facets have no counterparts in XForms

10.4 Usage Comparison

<xsd:element name="homepage">
  <xsd:simpleType base="uri">
    <xsd:pattern value="http:.+"/>
  </xsd:simpleType>
</xsd:element>

<uri name="homepage" scheme="http"/>

11.1 Declared as a SimpleType

<xsd:simpleType name="binary" base="xsd:binary"/>

11.2 Similarities

• none.

11.3 Differences

• XForms type facet has no direct counterpart in XML Schema.

• xsd:encoding,xsd:length,xsd:minLength, andxsd:maxLength facets have no counterparts in XForms

11.4 Usage Comparison

<xsd:element name="uploadFile">
  <xsd:simpleType base="binary">
    <xsd:encoding value="base64"/>
    <!-- cannot specify MIME type -->
  </xsd:simpleType>
</xsd:element>

<binary name="uploadImage" type="image/jpeg"/>